Research Note: The infectious bursal disease (Gumboro disease) vaccination scheme affects the quantitative and qualitative carcass characteristics and the immune response of Ross 308 broiler chickens

After different vaccinations, the study aimed to assess carcass composition, meat quality, and the level of the infectious bursal disease antibody titers in broiler chickens. In the experiment, 4 (30 chicks per group, 120 total) groups of Ross 308 broiler chickens (males and females) were included. Then, they were vaccinated at the hatchery. Group I was immunized against infectious avian bronchitis (IB) and Newcastle disease (ND) using vaccine A (20 mL/100 birds) and vaccine B (20 mL/100 birds), respectively, with injectable vaccine C (0.2 mL/each) targeting Infectious bursal' and Marek's diseases (MD). Group II received the same vaccinations for IB and ND, with separate injectable D vaccines for MD (0.2 mL/unit) and E for infectious bursal' disease (0.2 mL/each). Group III was similarly vaccinated for IB and ND; however, they received only vaccine D (0.2 mL/each) for MD, and on d 23, vaccine F was administered via drinking water against Gumboro disease (0.05 mL/each). Group IV served as the control and was not vaccinated. Ten carcasses from each group on d 42 were taken for carcass composition analysis and meat quality, including pH, color, and water-holding capacity (WHC). During rearing, on d 14, 28, and 42, blood was collected to determine the level of antibodies against infectious bursal' disease. Additionally, hematocrit (HCT), hemoglobin (HGB), and red blood cells were analyzed. In group I, a higher bursa of Fabricius weight than in the other groups was found (P < 0.001), and the liver weight was lower compared to group II (P = 0.020). In breast muscle, the pH₂₄ was higher in the control group than in group I (P = 0.036). Lightness (L*) in breast and leg muscles from group I was higher than in group II (P < 0.05). WHC was higher in group I than in group II (P = 0.025). The antibody titers of infectious bursal' disease was higher in group I on d 28 than in other groups (P < 0.05). Vaccine C (1 dose 0.2 mL/1 bird) of the reconstituted vaccine with the live recombinant virus strain vHVT013-69, not less than 3.6 - 5.0 log₁₀ PFU) had a beneficial effect.